I wonder if anyone else has this problem, if not it is yet another SDL problem on my platform.

All wintermute games (can easily be tested with Bickadoodle) seem to be squeezed on the X axis (probably due to those black bars on top and bottom) when playing/displaying it in fullscreen.
Switching to window mode and everything is fine. That is with no specific renderer, all display that beahviour, which leads me to believe it's a driver problem(?)

The worst thing is, that i cannot make out what is written, which makes story and text driven games unplayable.

My question to the wme maintainers, are those black bars intended?
Could it be a problem of the engione implementation (i guess not, since i never heard of such a problem anywhere)?
Maybe it's a simple case of turning an option on/off, but i have yet to find it. (It's not Aspect Ratio)

I just tried quickly on macOS and I have no such issue. The aspect ratio of the display seems correct both in windowed and fullscreen mode. I tried both with 2x and OpenGL graphics modes. And in fullscreen mode, when I use a Fit to Window stretch mode, I get some small black bars on the side but none at the top and bottom.

I just tried quickly on macOS and I have no such issue. The aspect ratio of the display seems correct both in windowed and fullscreen mode. I tried both with 2x and OpenGL graphics modes. And in fullscreen mode, when I use a Fit to Window stretch mode, I get some small black bars on the side but none at the top and bottom.

I did some more testing with fullscreen and window and cycling thorugh the available modes with ScummVM's LCTRL+LALT+"+ or -".

In window mode i can get those resolutions to show up while cycling through them:
320x240 (not in Screenmode Prefs)
640x480
960x720 (not in Screenmode Prefs)
1280x960 (not in Screenmode Prefs)
1600x1200 (not in Screenmode Prefs)
and differnt sizes of
2540x1410
which is probably because the window will only draw up to the WB screen borders and due to it's own borders lose some of the max size of 2560x1440 (which is the max resolution i can get)

In fullscreen i can get those while cycling through them:
640x480
720x400
800x600
832x624
1024x768
1152x870
1280x800
1280x1024
1600x900
1680x1050
1920x1080
2560x1440
These are all screenmodes i have set up in screenmode prefs (according to my monitor's manual) except 1280x720. (Whcih doesn't seem to be picked up at all for some reason).

The window modes are not reduced to the above list though, as it can adapt (probably) any resolution it is asked for.
e.g. if i set up a scummvm window in 640x480 and start "Chivalry is not dead" (a game that asks for a 800x600 resolution, the window will perfectly switch to the asked resolution, resizing itself and displaying the game crisp and sharp.

The fullscreen mode however does nothing of the above.
If i start the game from a launcher resolution of 640x480, it will be cramped into that very resolution and will look squeezed, have hard to read fonts and overall look ugly.
IF i however start the game from a launcher reslution of 800x600, it will also be crisp and sharp

The problem i see is that fullscreen does not (opposite to the window mode) respect and/or change the resolution to what the game asks, which leads to the mentioned graphics issues.

Now would be the question, why and which one is the bad boy.
Since no one else seems to hvae this problem i'm suspecting SDL2 (on my platform).